Scroll configuration plays a very important role in the design of a scroll compressor. In a scroll compressor, a scroll fixed lap rising from a fixed plate of a fixed scroll and a scroll orbiting lap rising from an orbiting plate of an orbiting scroll are combined with each other to form compression chambers therebetween. As the moving orbiting scroll orbits around the fixed scroll, the “pockets” formed by the meshed scrolls follow the spiral toward the center and diminish in size, and thereby, the entering coolant is trapped in diametrically opposed pockets and compressed as the pockets move toward the center.
In operation, the orbiting scroll is driven to move relative to the fixed scroll in high speed that it is required to supply lubricant to the compression chambers for ensuring smooth operation of the scroll members during compression so as to reduce friction loss. Thus, it is an important issue for any scroll compressor about how to feed a proper amount of lubricant to its compression chambers. That is, if too much lubricant is supplied, system efficiency of the scroll compressor is reduced due to the happening of unwanted fluid compression phenomenon, and on the other hand, if inadequate lubricant is supplied, then the drastic friction between the fixed scroll and the orbiting scroll will cause damage to the scroll compressor.
Please refer to FIG. 1A and FIG. 1B, which are respectively a cross-sectional view of a conventional scroll compressor disclosed in U.S. Pat. No. 6,827,563 and the lubricating oil passage of the scroll compressor of FIG. 1A. The conventional scroll compressor 100 of FIG. 1A comprises a block 110, a fixed scroll 120, an orbiting scroll 130 and a crankshaft 140, in which the a fixed scroll 120, an orbiting scroll 130 and a crankshaft 140 are all disposed on the block 110.
As shown in FIG. 1A, there are compression chambers S1 formed by the meshed fixed scroll 120 and orbiting scroll 130. As the crankshaft 140 is connected to the orbiting scroll 130 in a eccentric manner to be used for bringing along the orbiting scroll 130 to orbits around the fixed scroll 120 while the fixed scroll remains fixed, the coolant trapped inside the compression chambers S1 is compressed continuously by moving it through successively smaller “pockets” formed by the orbiting scroll's rotation. In detail, when the orbiting scroll 130 is allowed to orbit around the fixed scroll 120, a circular orbit area is formed on the fixed scroll 120, and moreover, an oil opening 122 is formed in the circular orbit area while configuring an oil passage 124 in the fixed scroll 120 to be used for connecting the oil opening 122 to the compression chambers S1.
In FIG. 1A and FIG. 1B, the oil opening 122 of the orbiting scroll 130 is closed for stopping the lubricant 142 from entering the oil passage 124 while enabling the lubricant 142 to flow through the channel 144 boring through the center of the crankshaft 140 and thus fill the buffering chamber S2 enclosed between the orbiting scroll 130 and the block 110. When the orbiting scroll 130 starts to move in the circular manner relative to the fixed scroll 120, the movement of the orbiting scroll 130 will cause the oil opening 122 to open in a periodic manner for feeding the lubricant 142 to flow through the oil passage 124 and reach the compression chamber S1 so as to lubricate the fixed scroll 120 and the orbiting scroll 130.
However, as the buffering chamber S2 where the lubricant 142 settled can be categorized as a high pressure area, conventionally a regulating valve 126 is required to be installed in those conventional scroll compressor to be used for depressurize the lubricant 142 before it is fed into the compression chamber S1. Nevertheless, the addition of the regulating valve 126 not only will cause the manufacturing cost of the scroll compressor to increase, but also it will cause difficulty in both design and manufacture of the scroll compressor since the regulating valve 126 is disposed inside the fixed scroll 120.
In a conventional scroll compressor disclosed in U.S. Pat. No. 5,252,046, its oil opening is disposed on the sidewall of its block in a manner that it can be open/close by the relative movement of the orbiting scroll against the block and thus enables the lubricant to flow through the oil opening and enter the compression chamber for lubricating the fixed scroll and the orbiting scroll. However, the aforesaid arrangement will cause the oil opening to remain open for an excessively long period of time that is going to cause an uncontrollable amount of lubricant to be fed into the compression chamber and thus cause the compression efficiency of the scroll compressor to drop.